School-bus drivers and matrons are ready to launch a citywide strike tomorrow at 6 a.m. — a brutal work stoppage that would force the families of 152,000 kids to scramble for emergency alternatives.

“We are here today to announce that local 1181 will strike effective Wednesday morning,” Michael Cordiello, president of the Amalgamated Transit Union local, said yesterday at a Midtown press conference.

“This is not a decision that we arrived at lightly, but an action we must take,” added Cordiello.

He vowed the strike — called over an impasse on the issue of job protections, which the city removed from newly bid-out bus contracts — would last “until the mayor helps us end it.”

It would be the first city school bus strike in 34 years. The last one, in 1979, lasted three months.

The Department of Education has made contingency plans to hand out MetroCards to students and parents at schools, but tomorrow’s commute is expected to be anything but a smooth ride.

Students who ride yellow buses are being issued MetroCards at school today; they’re are good through the duration of the strike.

Any parents of bused students in second grade and below can also pick up free 30-day MetroCards starting tomorrow.

But MTA and DOE officials acknowledged that not all subway lines and buses will be able to read the cards immediately — and may not be able to do so until late Thursday.

“I don’t know how to manage,” fretted Fatima Raza, an assistant teacher at PS 139 in Flatbush, Brooklyn, who has three kids that ride the yellow bus to different schools.

She was among many parents worried about how to juggle the travel logistics and still manage to get to work on time.

“It will be very hard — and very inconvenient,” she said.

The DOE received 160,000 three-trip per day student Metrocards — which are only valid on school days — and 165,000 monthly cards for parents, according to the MTA.

The DOE typically reimburses the MTA for the student cards based on usage, while monthly MetroCards run $104 a pop.

If the strike lasts more than a month, the DOE will distribute more of the monthly passes.

Where public transit isn’t an option, parents can seek reimbursement for taxis or car services or get back 55 cents a mile.

The costs incurred would be on top of the $1.1 billion per year the city already pays to transport students in kindergarten through eighth grade to school.

DOE officials say the job protections sought by the union force companies that win new contracts to hire workers on the basis of seniority from companies that lose bus routes — making it virtually impossible to cut its costs.

“With its regrettable decision to strike, the union is abandoning 152,000 students and their families who rely on school-bus service each day,” Mayor Bloomberg said.

“Let me be clear: the union’s decision to strike has nothing to do with safety and everything to do with job protections that the city legally cannot include in its bus contracts,” he said, referring to a 2011 state appeals court ruling that made them illegal.

Buses for students in prekindergarten or younger will not be affected by the work stoppage, according to a spokeswoman for the bus union.